A firearm of this type is known from DE 196 16 397 C2 (Gühring et al.) and has proven extremely successful, in particular under difficult conditions, e.g. in the sand and mud test according to NATO AC225.
Similar firearms are known, for example, from DE-PS 478 630, together with the related patent DE-PS 459 454 (both from Kiraly), DE 28 12 732 A (Zedrosser), U.S. Pat. No. 2,941,449 (Reed), U.S. Pat. No. 4,604,942 (Benelli), U.S. Pat. No. 3,318,192 (Miller), U.S. Pat. No. 3,955,470 (Kruzell); likewise as assault rifles HK416, Steyr Aug, FN C.A.L. and US automatic rifle M16.
In military applications, large-scale police actions, or hunting expeditions, it is frequently necessary to carry firearms such as lockable self-loading firearms such that they are fire ready, or at least only secured and in the open, without any opportunity for cleaning the firearm. As a result, it is impossible to keep sand, dust and mud from accumulating in the firearm mechanism.
Moreover, the firearm is often heavily oiled for misconceived cautionary reasons. When the reloaded cartridge is no longer fully oil-tight, e.g. due to a harmful effect thereto during the reloading procedure, or for any other reason, oil can penetrate the cartridge, and have a negative effect on the propellant. This results in a so-called “dud shot.”
If a shot then needs to be taken in a dangerous situation, the firearm may jam, because either the returning breechblock is braked too strongly by accumulated dirt, or the effect of the combustion gas on the reload mechanism is insufficient because of an ammunition malfunction.
Further shots remain unaffected, because the breechblock movement sweeps the dirt aside, such that no more disruptions are to be expected with the subsequent cartridge.
The problems outlined above have all been solved ideally in the aforementioned DE 196 16 397 C2 (Gühring et al.)